Bunny HELP. need to potty train it!!!!!!!!!!!!?

i was wondering if anybody knew how to potty train a bunny. i have one that has a potty training rabbit box that i bought at a pet store and she only uses it when shes in her cage but when she's out she really doesnt use it. and she poops everywhere (constantly) like if she was marking her territory of some sort. i dont know how to stop her bec she's not like a dog wear they poop every hour or so. she just poops literaly every 30 seconds and i dont know why. either way, i need to find some potty training method. SOON.